It marked the slowest week for the market since the end of February, according to a weekly report published Monday by Donna Olshan, president of Olshan Realty. The report tracks contracts signed for homes priced at $4 million and above.

Ms. Olshan has attributed the briskness of luxury sales to sellers finally cutting deals and making price concessions after homes have languished on the market for a year or more. Data from last week’s sales underscore her point, as the 23 homes that went into contract sat on the market for an average 412 days and had an average markdown of 7% from their original listing prices.

The second-most expensive contract signed last week, a penthouse at Carlton House on the Upper East Side, offers a decent example of price concessions. The 3,500-square-foot, three-bedroom unit first hit the market in September 2013 for $22 million, but found a buyer three-and-a-half years later and for a 23% price cut. It went into contract at an asking price of $17.9 million, according to Ms. Olshan’s report.

Nine of the 23 contracts signed last week were for homes priced above $10 million. The most expensive among them was a duplex, four-bedroom condo at 515 Park Ave., which is selling for $35 million, the sixth contract reported so far this year priced north of $30 million, Ms. Olshan wrote in the report.